Setting PHP session variable on website by calling request from another site -

is possible set session variable on php site example b.com calling curl request php site example a.com?

here code, sending post request a.com site b.com/extauth.php

<?php session_start(); $url = 'http://b.com/extauth.php'; $params = array(   'login' => 'login',   'pwd' => 'pass' );  $ch = curl_init(); $curlconfig = array(    curlopt_url            => $url,    curlopt_post           => true,    curlopt_returntransfer => true,    curlopt_postfields     => $params,    curlopt_followlocation => true,    curlopt_cookiesession => true,    curlopt_cookiejar => 'cookie.txt', ); curl_setopt_array($ch, $curlconfig); $result = curl_exec($ch);  curl_close($ch); ?> 

script on extauth.php set session['login'] = true. when open site b.com after sending request curl, session['login'] undefined.

<?php session_start(); if(isset($_post['login'])&&($_post['pwd'])){    //aditionall logic here    $_session['login'] = true; } ?> 

but when try send request ordinary html form placed on a.com site, session variable set. here code of form placed on a.com site.

<form action="http:b.com/extauth.php" method="post">     <input type="text" name="login" id="login" value=""></td>     <input type="password" autocomplete="off" name="pwd" id="pwd" value="">     <input class="btn" id="btn_login" value="login" type="submit"> </form> 

anybody know doing wrong?